Evaluation of the Alignment of the Tibial Malleolus and Lateral Malleolus of the Fibula

J.Phys. Ther. Sci 23: 919-921, 2011 Evaluation of the Alignment of the Tibial Malleolus and Lateral Malleolus of the Fibula

Takashi Fukuhara, RPT, MS1,2), Masaaki Sakamoto, RPT, PhD2), Rie Nakazawa, RPT, PhD2), Makoto Kawagoe, RPT1), Shin-Ichi Sakurai, RPT, PhD1), Kazuo Kato, MD1)

1) Asakura Clinic, Seseragi Hospital: 249–1 Asakura-machi, Maebashi City, Gunma 371-0811, Japan. TEL: +81 27-265-6522, FAX: +81 27-265-6527, E-mail: [email protected] 2) Graduate School of Health Sciences, Gunma University

Abstract. [Purpose] The purpose of this study was to determine the intratester reliability of an instrument developed by us for assessing the alignment of the lateral malleolus of the fibula and medial malleolus of the tibia using digital calipers. [Subjects] Eight healthy men without any leg symptoms (29.9 ± 5.8 years) participated in this study. [Methods] Subjects were measured by placing the instrument on their left and right ankles. The distances determined by three-dimensional measurements (width, length, height) from the center of the heel to the bottom edge of the lateral malleolus and the bottom edge of the medial malleolus were measured to 0.1 millimeters. The intratester reliability was assessed using intraclass correlation coefficients (ICCs) and standard errors of measurement (SEM). [Results] Excellent intratester reliability was confirmed. The ICCs ranged from 0.87 to 0.97 with SEMs between 0.76 and 2.93. [Conclusion] The results confirm that our device has excellent reliability when assessing the alignment of the lateral and medial malleolus. Furthermore, the simple design of the device and its easy method of use render our evaluation method useful for physical therapy clinical settings. Key words: Device development, Three-dimensional Coordinates, Reproducibility (This article was submitted Jun. 21, 2011, and was accepted Jul. 27, 2011)

INTRODUCTION SUBJECTS AND METHODS

A lateral ankle sprain is one of the most common injuries Eight subjects (8 men) volunteered to participate in the among athletes and other young active adults1,2). Of study. The mean age of the subjects was 29.9 ± 5.8 years. particular concern is the high proportion (up to 70%) of All subjects provided their written informed consent before patients who suffer from repetitive ankle sprains and data collection. Subjects did not have lower extremity chronic symptoms after initial injury3). Several studies have injury at the time of testing. Each subject visited the examined the fibular position in subjects with ankle laboratory on 2 separate days to have measurements taken instability4–8). However, there is no definite opinion on the on both legs. same. Results have suggested the development of anterior The measuring instrument consists of a pedestal and 2 and posterior positional faults in individuals with ankle devices incorporating a caliper (carbon fiber digital caliper, instability. In previous studies, fluoroscopy4,6) and MRI Shinwa Rules Co. Ltd. Niigata, Japan; minimum reading, images5,7,8) were used to record the positional fault of the 0.1 mm). Props were placed vertically on the 4 corners of lateral malleolus; however, these methods are not the pedestal. Moreover, lines were vertically drawn on the convenient. Furthermore, all the evaluation methods used in pedestal, and the heel cup was installed on a pedestal at the previous studies involved only two-dimensional point of intersection of the lines. The reference point on the measurements. For a more exact evaluation, it is necessary pedestal was at the point of intersection of the lines. In one to evaluate with three-dimensional measurements. We of the devices (device 1), it was consist of calipers and developed an instrument to quantify the alignment of the column, it is possible to insert horizontal calipers and slide lateral malleolus of the fibula and medial malleolus of the these calipers along the column. Using device 1 and the tibia using digital calipers. It is a mechanical instrument pedestal, we measured the exact distance (length, width) which is very easy to use, and the purpose of this study was between the reference point and the measurement point. In to determine the intratester reliability of this instrument. the other device (device 2), calipers could be fitted, and the device could stand vertically. Using device 2, we could measure the exact height. In other words, using the devices, it is possible to calculate the three-dimensional coordinates of the measurement points. 920 J. Phys. Ther. Sci. Vol. 23, No. 6, 2011

Subjects were seated with their hip, knee, and ankle joints at 90°. A pad for fixation was then placed under the thigh to help maintain a neutral position. After the heel was in contact with the heel cup, the subject adopted a 10°-internal rotation of the foot vertical to the frontal plane (refer to the ankle radiographic methods9)), and a line was drawn connecting the center of the second toe with the heel. Subjects were observed to ensure that no rotations of the lower extremity occurred during testing. The lowest points of the lateral malleolus and medial malleolus were Fig. 1. Measurement of distance and calculation of position. measured. Measurements were taken after the sites were L: The lowest point of the lateral malleolus marking was confirmed by palpation and marked (Fig. 1). M: The lowest point of the medial malleolus After the marking and positioning, measurements were R: The reference point taken to determine the position of the measurement sites. ·The distance in the sagittal plane between L and A The reference point was defined as the point at which the represented by X. vertical line intersects the posterior margin of the calcaneus ·The distance in the sagittal plane between L and B and the ground. The distance between the reference point represented by Y. and the measurement point was recorded (length, X; height, ·The distance in the frontal plane between L and D, and M and C represented by Z. Y; width, Z) (Fig. 1). The same examiner performed the *At the side of the medial malleolus, the measurement positioning and took measurements for all subjects. was performed in the same manner. To compare the intratester reliability of the device we developed, intraclass correlation coefficients (ICC1, 1) were calculated for measurements taken on the 2 days. In addition to ICC values, the standard errors of measurement Table 1. Mean and standard deviation (SD) values of the (SEM) were also calculated. Both ICCs and SEMs were lateral malleolus and the medial malleolus. calculated for the measurement values of the lateral Mean SD malleolus and the medial malleolus. X (mm) 32.3 11.5 The lateral malleolus Y (mm) 57.3 3.0 RESULTS Z (mm) 39.8 7.8 X (mm) 45.2 11.7 Descriptive statistical values for the lateral malleolus The medial malleolus Y (mm) 80.8 3.5 and medial malleolus are presented in Table 1. The Z (mm) 24.5 9.6 intratester reliability of measurement values of the lateral malleolus of the fibula and medial malleolus of the tibia are shown in Table 2. The ICC values ranged from 0.87 to 0.97 with standard errors of measurement between 0.76 and Table 2. Mean absolute differences, intraclass correlation 2.93. coefficients (ICCs), and standard error of measurement (SEM) obtained at 2-day intervals. DISCUSSION Mean difference ICC SEM X 0.2 0.97 2.86 The purpose of this study was to determine the intratester The lateral malleolus Y 0.4 0.84 0.76 reliability of a device we developed for assessing the Z 0.8 0.87 1.96 alignment of the lateral malleolus of the fibula and medial X 1.2 0.95 2.93 malleolus of the tibia. We consider measurements made The medial malleolus Y 0.5 0.88 0.86 with our device of the position of the medial malleolus and Z 1.6 0.88 2.41 lateral malleolus are highly reproducible. According to previous studies, the ICC values obtained in this study (ranging from 0.84 to 0.97) indicating almost perfect reproducibility10). We consider the results of the present we only collected intratester reliability data. Therefore, we study are comparable to those of previous studies in which still need to determine whether the findings can be fluoroscopy and MRI images were used. The results confirm generalized between different testers. It is necessary to that the alignment of the lateral and medial malleoli can be examine the intertester reliability and demonstrate that our assessed with excellent reliability using our device. In method can be applied in general. Second, it should be addition, previous studies have used a two-dimensional noted that our study subjects were free from lower- evaluation method4–8), whereas our evaluation method extremity injury at the time of testing. In cases of pathology, allows three-dimensional measurement. Furthermore, the the presence of swelling and deformity may introduce a simple design of the device and its ease of use render our potential error in both the reliability and validity of the evaluation method useful for physical therapy clinical measurements taken using our device. Further work is settings. needed to assess the feasibility of using our method for There were some limitations to the present study. First, patients with clinical pathologies of the foot and ankle. 921

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